Meaning in this text
Sacred pilgrimage sites associated with divine events or the presence of sages. The Bhagavatam lists numerous tirthas but teaches that merely hearing the Bhagavatam is more purifying than visiting all the tirthas in the world.
On this site, Tirthas is treated as a reading aid rather than a final doctrinal definition: use it to move from a question about a term into the chapters where the term actually appears.